Somsak Panha

Chulalongkorn University · Department of Biology

The taxonomy of the pill millipede genus Rhopalomeris Verhoeff, 1906, which is restricted to Indochina and currently comprises six described species, is refined and updated. An integrative taxonomic approach was employed that combines morphological examination with DNA barcoding using the cytochrome c oxidase subunit I (COI) gene for species identi...

The poorly studied leatherleaf slug genus Valiguna in Thailand was carefully investigated. Members of this genus are phenotypically similar, making their identification very challenging. This study clarifies the taxonomic status of all Valiguna species in Thailand by combining morphological and anatomical studies with DNA barcoding. Monophyly of al...

The Malay Peninsula has traditionally been considered to harbour a diverse land-snail fauna, both in terms of a high species richness and a wide variety of conchological traits, especially within the limacoid land snails. A recent survey along the Malay Peninsula of southern Thailand discovered an overlooked limacoid taxon “ Trochomorpha ” sculptic...

The taxonomy of subulinid snails in Myanmar has been evaluated, resulting in the recognition of 40 species and subspecies across nine genera: Allopeas, Bacillum, Curvella, Glessula, Opeas, Paropeas, Rishetia, Tortaxis, and Zootecus. Nine species are re-described based on recently collected specimens, and two new species, Glessula mandalayensis Man...

The semislug Megaustenia siamensis, commonly found in Thailand, is notable for its exceptional capacity to produce biological adhesives, enabling it to adhere to tree leaves even during heavy rainfall. In this study, we generated the first reference genome for M. siamensis using a combination of three sequencing technologies: Illumina’s short-read,...

Durgella is a terrestrial semislug genus in the family Helicarionidae and currently comprises nine species recorded from Thailand and Myanmar. Two species, D. concinna and D. rhaphiellus, have been described based only on shell information, while the taxonomy of the remaining seven species is comprehensively treated herein using comparative morphol...

The mechanism of bioluminescence in the luminous land snails remains largely unknown. Here, we analyzed basic biochemical properties of the luminous land snail, Quantula weinkauffiana . The luminescence activity was extracted from the light organ located near the mouth using a neutral buffer containing detergent. The reaction of the crude buffer ex...

Thai species of the pill millipede genus Hyleoglomeris Verhoeff, 1910 are reviewed, and an annotated catalogue is provided. Six new species from Thailand are described and illustrated based on morphological characteristics and molecular analyses: H. dracosphaera sp. n., H. nigromaculata sp. n., H. suwannakhuhensis sp. n., H. bomba sp. n., H. tongke...

Land snails were collected for the project ‘Conserving Myanmar’s Karst Biodiversity’ from the limestone karsts in Mon, Kayin, and Shan states and in the regions of Tanintharyi and Mandalay between 2015 and 2017, through cooperation with Fauna and Flora International (FFI) and the Forestry Department of Myanmar. Here, we report on a portion of the c...

The marine littoral earthworm Pontodrilus litoralis (Grube, 1855) is widely distributed and is reported as a single species. This study utilized an integrative taxonomic approach based upon morphological examination, phylogenetic reconstruction, and molecular species delimitation, to test whether the taxon is a single species or a species complex....

Recent taxonomic revision of the strikingly ornamented millipedes known as ‘dragon millipedes’ in the family Paradoxosomatidae, has revealed generic division into six genera. The majority of species are distributed in mainland South-East Asia and each genus is restricted to a well-delimited area. However, their evolutionary history has remained poo...

The status of the indigenous Southeast Asian apple snails belonging to the genus Pila is of concern due to their fast rate of population decline, possibly as a result of multiple factors including habitat loss or disturbance and the introduction of globally-invasive apple snails, Pomacea spp. Conservation actions, including captive breeding of the...

The mysterious world of the bioluminescent molluscs in terrestrial ecosystems is mesmerizing, but Quantula striata was previously the only terrestrial mollusc known to be luminescent. Here, we document the new discovery of bioluminescence in four land snails, namely Phuphania crossei , P. globosa , P. carinata , and P. costata. Our observations est...

The Euconulidae is a globally distributed land snail family but there is no record of this family from Thailand. In this study, we describe a new genus, Siamoconus gen. nov., based on comparative studies of the shell characteristics, external morphology of animals, radula, genital and spermatophore structures, and molecular phylogeny. We performed...

Earthworm specimens collected from Sakon Nakhon and Nakhon Phanom, northeast Thailand, were found to contain four new species in the family Megascolecidae, with one species in the genus Metaphire Sims & Easton, 1972, and the other three in the genus Amynthas Kinberg, 1867. These are herein named Metaphire songkhramensis Chanabun & Panha, sp. nov. i...

The Asian buffalo leech Hirudinaria manillensis is an obligatory ectoparasite freshwater leech, feeding on blood of vertebrates. Its natural populations have been threatened by habitat destruction and overexploitation for traditional medicine. In this study, we developed 18 species-specific microsatellite markers for H. manillensis using a next-gen...

The pill millipede genus Hyperglomeris Silvestri, 1917 is reported from Laos for the first time. Two new species, namely H. bicaudata Likhitrakarn, sp. nov. and H. inkhavilayi Likhitrakarn, sp. nov., from Houa-phanh and Khammouane provinces, northern Laos, are described and illustrated based on morphological characters and molecular analyses. Seque...

This study presents a complete species list of the door snails inhabiting Myanmar, updated to now include 33 taxa, and provides taxonomic notes together with a re-description of the shell, radula, and genitalia for 13 species and subspecies, including Oospira philippiana , the type species of the genus Oospira . The snails previously treated as sub...

Phylogenetic analyses using mtDNA gene sequences revealed the presence of two genetic clades in the genus Leptobrachella (former Leptolalax) from northern Thailand. One formed a clade including L. ventripunctata and L. aerea, while another included L. bourrreti and L. laoi. The first clade contained L. cf. minima from Doi Suthep, while the second c...

The snorkel snail genus Rhiostoma Benson, 1860 is comprised of terrestrial cyclophorid snails with wide-ranging species diversity and radiation in Southeast Asia. The typical characters of the genus are a depressed shell, a detached and descending portion of the last whorl with a distinctive peristomal breathing device attached, and a calcareous cu...

Leeches in the genus Hirudinaria Whitman, 1886, also known as buffalo leeches, are blood-sucking ectoparasites of vertebrates. Although they are widely distributed in Asia and had been highly abundant in the past, studies on diversity and taxonomy of this genus are still scarce. There is probably a large amount of cryptic diversity yet to be discov...

The cosmopolitan littoral earthworm Pontodrilus litoralis is distributed in tropical and sub-tropical coastal habitats, whereas P. longissimus is reported only in the Thai-Malay coastal line. In the present study, we examined the difference in salinity effect on the survival rate, wet weight (hereafter weight) change, behaviour, and osmolality of t...

Thailand is located at the crossroads of several biogeographical regions, and boasts a high level of biodiversity, especially among the malacofauna. The most recent checklist of land snail species in Thailand was compiled more than twenty years ago, and so this checklist needs revision and the addition of newly discovered taxa. This study updates t...

A new genus of the millipede family Pseudospirobolellidae, Siliquobolellus gen. nov. , is described from limestone mountains in Thailand, based on three new species, viz. Siliquobolellus amicusdraconis gen. et sp. nov. from Uthaithani Province, Siliquobolellus constrictus gen. et sp. nov. from Prachuap Khiri Khan Province and Siliquobolellus prasan...

The carnivorous terrestrial snail family Streptaxidae, recognized by having a regular to eccentric shell with complex apertural dentition, remains little-known and largely unexplored in Myanmar. This article presents historically recorded species and provides new data on this family. A total of eighteen species in five genera, namely Carinartemis ,...

Salween River basin’s karst ecosystems in southeastern Myanmar remain largely unexplored and are likely to harbour a high terrestrial snail diversity that are often associated with high levels of snail endemism. Here, an outstanding group of new karst-associated terrestrial snails, Burmochlamys gen. nov. , are discovered. A study of the comparative...

The speciose land snail genus Sarika is widely distributed throughout mainland Southeast Asia. This genus is generally recognized by a smooth and polished shell. However, we recognize four species with a ribbed shell surface ( S. siamensis, S. theodori, S. costabilis sp. nov., and S. costata sp. nov.) exhibiting genital characters similar to those...

Hitherto, the millipede genus Apeuthes (family Pachybolidae, subfamily Trigoniulinae) was only known from three species described in Vietnam based on morphological characters. The present study uses two partial mitochondrial gene fragments (cytochrome c oxidase I (COI) and 16S ribosomal RNA) and morphology to define four new Apeuthes species from M...

The Oriental genus Nepalella is reviewed, rediagnosed and shown to comprise 28 species, including N. siamensis sp. nov. from southeastern Thailand. All Nepalella species are keyed, and their distributions mapped, being highly localized and mainly allopatric. Unlike most congeners, which are largely confined to subtropical environments (including mo...

Knowledge of Thai semislugs remains scarce, especially the dancing semislug genus Cryptosemelus. Prior to the present study, only a single species has been recognized with little available information. To address this knowledge gap, we surveyed for semislugs in western and southern Thailand, which yielded three species belonging to the genus Crypto...

This study aims to identify the flower visitors of Mucuna thailandica (Fabaceae), endemic plant species in montane forests in Thailand, to determine their potential pollinators. The genus Mucuna produces papilionaceous flowers and has an explosive flower‐opening step. Explosive opening rapidly exposes stamens and pistil from keel petals and release...

Objective Snails secrete different types of mucus that serve several functions, and are increasingly being exploited for medical and cosmetic applications. In this study, we explored the protein pattern and compared the biological properties of the mucus secreted from the mantle collar and foot of two snail species, Lissachatina fulica and Hemiplec...

An enigmatic land snail species restricted to the karst ecosystem in southern Cambodia and formerly placed in the family Ariophantidae is now reclassified into the family Dyakiidae. Its current systematic position is based on morpho-anatomical characters combined with a molecular phylogeny based on two partial mitochondrial markers (COI and 16S rDN...

Thai limestone karsts are known to contain a rich biodiversity of animals, especially terrestrial snails, but still require further intensive exploration to evaluate their biodiversity. To date, only a few studies on the limestone karst-inhabiting land snail genera have been published. The present work focuses on the species diversity and phylogene...

The type series boundary and the name-bearing type designation of each cyclophorid taxon originally described by Godwin-Austen are clarified based on an interpretation that complies with the ICZN. Previ- ous statuses of type specimens designated by previous authors are reconsidered. Lectotypes of Spiraculum oakesi Godwin-Austen, 1915, Spiraculum...

The genus Hemiplecta is a group of large-sized land snails which have long been used as a food resource by Indochinese people. There are five dextral and four sinistral species currently recognized from Thailand. The dextral group is comprised of two previously recorded species ( H. humphreysiana and H. distincta ), two newly recorded species ( H....

The diversity of Indochinese prawns in genus Macrobrachium is enormous due to the habitat diversification and broad tributary networks of two river basins: the Chao Phraya and the Mekong. Despite long-standing interest in SE-Asian decapod diversity, the subregional Macrobrachium fauna is still not yet comprehensively clarified in terms of taxonomic...

The predominantly Indochinese to southern Chinese millipede genus Tylopus presently comprises 76 described species, including two new, T. monticola sp. nov. and T. sutchariti sp. nov., both described and illustrated based on material from a limestone mountain in Taunggyi District, Shan State, Myanmar. Both new species have been found to occur synto...

A joint expedition between the Natural History Museum, London and Vietnamese colleagues discovered living populations of the charismatic tree snail, Amphidromus (Amphidromus) cambojiensis (Reeve, 1860 Reeve L. 1860. On two new species of shells from Cambojia. Ann Mag Nat Hist, Ser 3. 6:203–204. doi:10.1080/00222936008697308.[Taylor & Francis Online...

Pontodrilus litoralis is a cosmopolitan littoral earthworm known to exhibit bioluminescence. Recently, a congeneric species, Pontodrilus longissimus, from Thailand was described. These species are sympatric, but their burrowing depths on Thai beaches are different. In this study, we examined the in vivo and in vitro bioluminescent properties of P....

Objective: Snails secrete different types of mucus that serve several functions, and are increasingly being exploited for medical and cosmetic applications. In this study, we explored the protein pattern and compared the biological properties of the mucus secreted from the mantle collar and foot of two snail species, Lissachatina fulica and Hemiple...

Northeastern Thailand relies on agriculture as a major economic activity, and has used high levels of agrochemicals due to low facility, and salty sandy soil. To support soil recovery and sustainable agriculture, local farmers have used organic fertilizers from farmed animal feces. However, knowledge about these animal fecal manures remains minimal...

Indochina land snails of the family Ariophantidae are in need of thorough systematic revision. Here we comprehensively revise the systematics of the large-shelled, sinistral (counterclockwise) coiling snails from Thailand and Peninsular Malaysia. Molecular phylogeny based on mitochondrial ( coi and 16S) and nuclear (28S) gene sequences demonstrates...

Members of the terrestrial snail family Dyakiidae from Southeast Asia show a distinct geographical distribution pattern and possess different degrees of complexity in their amatorial organ gland. This study is the first molecular phylogeny of ten of the 12 genera in this family, performed to provide insights into the origin of Dyakiidae and the evo...

Members of the terrestrial snail family Dyakiidae from Southeast Asia show a distinct geographical distribution pattern and possess different degrees of complexity in their amatorial organ gland. This study is the first molecular phylogeny of ten of the 12 genera in this family, performed to provide insights into the origin of Dyakiidae and the evo...

Specific status and species boundaries of several freshwater prawns in the Macrobrachium pilimanus species group remain ambiguous, despite the taxonomic re-description of type materials and additional specimens collected to expand the boundaries of some species. In this study, the "pilimanus" species group of Macrobrachium sensu Johnson (1958) was...

Citation: Srisonchai R, Likhitrakarn N, Sutcharit C, Jeratthitikul E, Siriwut W, Thrach P, Chhuoy S, Ngor PB, Panha S (2020) A new micropolydesmoid millipede of the genus Eutrichodesmus Silvestri, 1910 from Cambodia, with a key to species in mainland Southeast Asia (Diplopoda, Polydesmida, Haplodesmidae). ZooKeys 996: 59-91. https://doi. Abstract T...

Pontodrilus litoralis is a cosmopolitan littoral earthworm known to exhibit bioluminescence. Recently, a congeneric species Pontodrilus longissimus from Thailand was described. These species are sympatric but their burrowing depths on Thai beaches are different. In this study, we examined the in vivo and in vitro bioluminescence properties of P. lo...

Sophina is a poorly known and neglected genus due to the inaccessibility of the Salween Basin, Southern Myanmar. Taxonomic status, distribution, and phylogeny are being revised based on an integrative analysis of genitalia, radula, and molecular data. Morphological variation in shells and genitalia, together with a phylogenetic tree from concatenat...

Members of the land snail genus Sarika Godwin-Austen 1907 are superficially similar and difficult to differentiate by their shell morphology so that their species limits are still unclear. In order to resolve the taxonomy of this group, a phylogenetic reconstruction of Sarika is presented, based on morphological and anatomical characters, as well a...

Ampullariidae include the largest of all freshwater snails and are of ecological, evolutionary and anthropogenic importance in Southeast Asia (SEA). Native ampullariids belonging to the genus Pila face various threats but are understudied, with their species taxonomy being confused and data on their distributions being scarce. We provide a comprehe...

This study investigated different bacterial communities in three intestinal parts (foregut, midgut and hindgut) of Xylocopatenuiscapa to understand the roles of gut bacteria. Our phylogenetic analysis revealed that X. tenuiscapa is closely related to Xylocopa latipes. The 16S rRNA gene in the genomic DNA samples from the gut was examined by illumin...

Land snail surveys conducted in northern Laos between 2013 and 2014 have led to the discovery of a living population of Trichelix horrida (Pfeiffer, 1863). This species has never been recorded from specimens other than the types, and its distribution and anatomy have remained essentially unknown. The genitalia and radula morphology are documented h...

Southeast Asia boasts a high diversity of carnivorous terrestrial snails in the family Streptaxidae. Six genera are now recognized in this region, mainly classified by the traditional characters of shell morphology, especially the configuration of the apertural dentition and eccentric shell shape. More recently, genital characters have been used to...

Prior to this study, few collections and records were made of the land snails in Cambodia and the historical taxa had never been reviewed. Herein a report on the land snail diversity based on specimens collected recently from karstic and non-karstic areas in southern Cambodia is provided. This checklist presents 36 species of land snails (two Nerit...